Automatic Telephone Practice
General Books, May 17, 2012 - 56 pages
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1919 Excerpt: ... XXIV The Reverse Battery Repeater. Referring' to Fig. 47 we find the familiar line relay L and the release relay R. The reverse battery relay A is a 1,300 ohm relay, and operates to reverse the polarity of the calling line. The condenser cut-off relay D is a slow acting relay of 325 ohms resistance. The electro polarized relay C has an upper winding of 1,900 ohms and a lower winding of 60 ohms resistance. The impedance coil B is 500 ohms in resistance. Let us assume that a connection has been extended to this repeater. The line relay L will energize and close the circuit of the release relay R, which in turn will energize and place ground on the release trunk. Upon the energization of relay L a circuit may be traced from ground, thru the lower winding of relay L of the selector at the distant office, lower winding of relay C, impedance coil B, make springs relay L, upper winding of the line relay L of the selector at the distant office, to negative battery. The line relay of the selector at the distant office will energize over this circuit and stand in readiness to receive the impulses which will be sent it by the repeater. When the release relay energized a circuit was closed from ground, make springs relay R, upper winding of relay C, to negative battery. The current flowing in the two windings of relay C will at this time oppose each other, and as a result the relay will not operate. It is furthermore to be understood that the upper winding of relay C is not strong enough to operate the relay when it alone is energized. When the subscriber dials the next figure in the number, a 6 for example, the line relay L will momentarily release itsj armature six times. Each time the relay L de-energizes a circuit is closed from ground, break springs relay L, make...
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